Impacts of organic loading rate and hydraulic retention time on organics degradation, interspecies interactions and functional traits in thermophilic anaerobic co-digestion of food waste and sewage sludge

Xingxing Zhang; Pengbo Jiao; Ming Zhang; Peng Wu; Yufeng Zhang; Yiwei Wang; Kaiyan Xu; Jiazhou Yu; Liping Ma

doi:10.1016/j.biortech.2023.128578

Impacts of organic loading rate and hydraulic retention time on organics degradation, interspecies interactions and functional traits in thermophilic anaerobic co-digestion of food waste and sewage sludge

Bioresour Technol. 2023 Feb:370:128578. doi: 10.1016/j.biortech.2023.128578. Epub 2023 Jan 4.

Authors

Xingxing Zhang¹, Pengbo Jiao¹, Ming Zhang¹, Peng Wu², Yufeng Zhang¹, Yiwei Wang¹, Kaiyan Xu¹, Jiazhou Yu¹, Liping Ma³

Affiliations

¹ Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, PR China.
² School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, PR China.
³ Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, PR China. Electronic address: lpma@des.ecnu.edu.cn.

PMID: 36610483
DOI: 10.1016/j.biortech.2023.128578

Abstract

This study provided novel insights into the effects of organic loading rate (OLR) and hydraulic retention time (HRT) on thermophilic anaerobic co-digestion of food waste and sewage sludge. The obtained maximum methane (CH₄) yield of 328 ± 4 mL CH₄/g COD_fed at HRT of 15 days (OLR = 5.8 g VS/L/d) was partly attributable to the enhanced acidogenesis, acetogenesis, and methanogenesis phases. The increased key enzyme activities, particularly acetate kinase (improved by 5.2-fold), providing substantial methanogenic substrates for efficient CH₄ production. The functional syntrophs that were related to syntrophic decarboxylation, novel acetate oxidation & reductive acetyl-CoA, and β-oxidation pathways could drive trophic interactions with methanogens. This markedly stimulated hydrogenotrophic Methanoculleus thermophilus metabolism and concomitantly enriched mixotrophic Methanosarcina thermophila. The distinctive cross-feeding interspecies interactions significantly affected the assembly and dynamics of thermophilic consortia. These findings shed light on the physicochemical and microbial mechanisms of HRT- and OLR-dependent enhancement of methanogenesis.

Keywords: Anaerobic co-digestion; Hydraulic retention time; Influencing mechanisms; Metagenomic binning; Organic loading rate.

MeSH terms

Anaerobiosis
Bioreactors
Digestion
Food
Methane / metabolism
Refuse Disposal*
Sewage*

Substances

Sewage
Methane